This invention relates to fluid-treatment devices.
The invention is more particularly concerned with medical devices for filtering, humidifying or otherwise treating fluid, such as air, flowing to or from a patient.
In one particular application of medical respiration systems, a filter or HME device is connected at the machine end of a tracheal tube and connection to the device is made by a so-called catheter mount, that is, a relatively large bore, corrugated, flexible tube. The catheter mount provides a flexible interconnection between the tracheal tube and ventilator tubing connected at the other end of the catheter mount. One problem, with filters in particular, is that high efficiency filters tend to have a high resistance to flow unless they have a large surface area, in which case they tend to be bulky and heavy. It is also a disadvantage to have several different components interconnected in a breathing circuit because it makes rapid assembly more difficult, it increases the deadspace within the circuit and it increases the risk of accidental detachment of components. Proposals have been made to overcome some of the problems of previous arrangements, as described in GB2321604 and GB2169522. Previously proposed arrangements, however, suffer from various problems, such as difficulties in making the filter element or of sealing it in a housing.
It is an object of the present invention to provide an improved fluid-treatment device.
According to one aspect of the present invention there is provided a fluid-treatment device comprising a housing and a fluid-treatment element located in the housing to treat fluid flowing through the housing, the housing having an inlet and outlet port and being of elongate shape divided along its length into two parts, each part having a set of triangular tooth formations extending along opposite sides that mate with one another, the fluid-treatment element being pleated across its width in a zigzag fashion with the sides of the fluid-treatment element following the profile of the teeth formations on the housing, and opposite edges of the fluid-treatment element being supported and sealed between the teeth formation of the two parts of the housing such that fluid flowing between the two ports is confined to flow through the fluid-treatment element.
The housing is preferably flexible and corrugated. The two parts of the housing may be substantially identical. The fluid-treatment element is preferably a gas-treatment element such as an HME element or a filter. One of the parts of the housing preferably has a patient end fitting for connection to a tracheal tube connector, the other of the parts having a machine end fitting for connection to a ventilation tube connector. The two parts of the housing may be sealed with the fluid-treatment element by means of an adhesive or solvent along opposite edges of the fluid-treatment element. The fluid-treatment element may be supported by a ladder-shape support frame. The support frame may be of a thermoplastic material and the two parts of the housing may be sealed with the fluid-treatment element by causing material of the support frame to flow into sealing contact with both the fluid-treatment element and the two parts of the housing.
According to another aspect of the present invention there is provided an assembly including a fluid-treatment device according to the above one aspect of the invention, a tracheal tube, a connector connected between the tracheal tube and one end of the fluidtreatment device, ventilation tubing, and a connector connected between the ventilation tubing and the other end of the fluid-treatment device.
A catheter mount incorporating a filter, according to the present invention, will now be described, by way of example, with reference to the accompanying drawings.